Alarm system



Aug. 19, 1947. F. F. DENZLER ALARM SYSTEM Filed April so, 1946 2Sheets-Sheet 1 INVENTOR.

Fsux ,F. Denna:

F. F. DENZLER Aug. 19, 1 947.

ALARM SYSTEM 2 Sheets-Sheet 2 Filed April 50, 1946 THIS 5mm Ar OddNUMBERED I I I I I l I I I I l E I I Main Loop I l I l I I l l l I I JINVENTOR. FELIX F. DENZLEI2.

fizzorney .IIIIIIIII Patented Aug. 19, 1947 ALARM SYSTEM Felix F.Denzler, Pomona, Calif.

Application April 30, 1946, Serial No. 665,930

17 Claims.

This invention relates to electrical safety devices, such as burglar andfire alarm systems, and has to do more particularly with systems of thetype shown in my prior Patent 2,300,409 in which a plurality ofsub-stations at difierent locations are connected in series in a commonline circuit emanating from a central station.

A broad object of the present invention is to increase the efliciencyand utility of an alarm system of the type disclosed in my prior Patent2,300,409.

A more specific object is to provide an alarm system of the typereferred to in which the location of a temporary trouble condition canbe determined by tests from the central station even after the troublecondition has corrected itself.

.Another specific object is to provide an alarm system of the typereferred to which is extremely difficult, if not impossible, tocircumvent and which will indicate the location of an abnormal conditionin any part of the system.

Other specific objects and features of the invention will appear fromthe description to follow with reference to the drawing, in which:

Fig. 1 is a schematic diagram showing the general layout of a system inaccordance with the invention, the circuit at the central station beingshown in full;

Fig. 2 is a schematic diagram showing the apparatus and circuit at oneof the sub-stations;

Fig. 3 is a schematic diagram showing the condition of a portion of theapparatus at a substation under normal conditions when current isflowing in one direction in the line;

Fig. 4 is a schematic diagram similar to Fig. 3 but showing the circuitsthrough the apparatus when no line current is flowing;

Fig. 5 is a schematic diagram similar to Figs. 3 and 4 but showing thecircuit condition when current is flowing in direction opposite to thecurrent fiow in Fig. 3; and

Fig. 6 is a detail diagram showing the lock switch of Fig. 2 in dayposition.

As previously indicated, this system is a further development of thesystem shown in my Patent 2,300,409, and to simplify comparison of thetwo systems and an understanding of the improvements introduced inaccordance with the present invention, elements of the present systemcorresponding in general to elements of the system of the prior patentbear the same reference characters.

The complete circuit shown in Fig. 1 shows a system incorporating acentral station, which is enclosed within the dotted line 50, and foursubstations which are identified as ST#1, ST#2,

ST#3 and ST#4. The number of sub-stations may be either less or greaterthan four, this numher being chosen merely for purpose of illustration.It will be observed that two lines emanate from the central station. Oneof them, identified as LI, extends to the sub-station ST#1; a secondline L2 interconnects sub-station ST#1 and ST#2; a third line L3interconnects sub-stations ST#2 and ST#3; and a fourth line L4interconnects sub-stations ST#3 and ST#4. The circuit is completed fromsub-station ST#4 back to the central station over a fifth line L5. Thedetails of the apparatus and circuits at the substations will bedescribed later with reference to Figs. 2 through 5.

Central station apparatus The apparatus at the central station includesfive relays identified, respectively, as V, LRI, T, LE5 and C. Inaddition, the central station includes six keys or switches G, R, P, Q,F and E, respectively, resistors 80, 82, BI and 83, a main battery 5!,an auxiliary battery 52, a push button U, an alarm bell 51, a red signallamp Irrd and an annunciator 54 having a pair of actuating magnets 55and 56 and a pair of hands 62 and 12.

One terminal of the battery 51 is permanently connected to ground andthe other terminal will be hereinafter referred to as battery inaccordance with common practice in the signalling art. Normally, batteryis connected to .the line LI, and the circuit is shown in heavy lines inFig. 1. Thus current flows from battery through resistor 82. throughresistor 80, through relay LR! thence through relay T and through rela Vto line Ll.

The circuit from ground may be traced over contacts l and B of switch F,a test jack 84, thence through contacts 8 and 9 of switch F throughrelay LR5 and through contacts 3 and 4 of switch Q to line L5.

Normally a circuit is completed from line Ll to line L5 through thesub-stations, and a current flows to maintain the relays V, LRI and LE5energized. The line current also flows through relay T, but this is amarginal relay and does not pull on normal line current.

so long as there is no interruption in the current flowing throughrelays LRI and LRB and the magnitude of the current is insufficient topull relay T, the alarm relay C remains energized, under which conditionthe alarm bell 51 and the alarm light Lrd are deenergized. As willappear from the description to follow, any abnormal condition in thesystem releases the relay C which then completes energizing circuits tothe hell 5? and the lamp Lrd from the auxiliary bat- 3 tery 52. Byemploying the auxiliary battery, actuation of the alarm bell and lamp isassured even though the release of relay C should result from failure ofthe main battery It Will be observed that the alarm relay C i normallyenergized from the battery 5|. The circuit may be traced from batteryover the contacts I and 2 and through the winding of relay C, thencethrough the normally closed contacts of relay T, thence through contacts3 and 4 of relay LRI, thence through contacts 6 and 5 of switch P,thence through contacts 3 and 4 of relay LR5 to ground. Since thecircuit includes front contacts of relays LRI and LR5 and back contactsof relay T, relay C must drop in the event of release of either relayLRI or relay LR5 or pulling of relay T.

After having been released, relay C remains down since its circuit isopened at its contacts I and 2. However, if the rest of the circuit iscompleted up to the relay C, the latter can be operated by pressing thepush button U, after which the relay will hold up.

The relay V is permanently connected in series with line LI andfunctions to indicate flow of current from line LI into the centralstation under certain test conditions to be described later.

As previously indicated, relay T is a marginal relay which responds toexcess current flow to the line to give an alarm by opening its contactswhich are in the alarm circuit previously traced.

Relay LRI functions to open the alarm circuit in response to reductionof the current flow to line LI below a predetermined value. It alsofunctions, during a testing operation, to energize the magnet 55 of theindicator 54 over its contacts I and 2 to count sub-stations.

Relay LR5 ftmctions to open the alarm circuit in case of failure ofcurrent flow from line L5 into the sub-station. It also functions,during a testing operation, to energize the magnet 56 of the annunciator54 and count stations.

The resistor 82 is provided for the purpose of adjusting the normal linecurrent to a value such that it will hold relay LRI but Will not pullrelay T.

The function of resistor 83 is to adjust the current flowing throughrelay LR5 under emergency operating conditions, to be described later,to compensate for reduction in line resistance and produce normalcurrent through relay LR5.

Resistors 89 and 8| are provided for the purpose of increasing thecurrent to lines LI and L5, respectively, during operations forresetting the sub-station apparatus which will be described later.

The switch P is provided for the purpose of grounding the circuitbetween the line relay LRI and the marginal relay T to hold the relayLRI and provide a path from ground from line LI while applying currentfrom the central station to line L5 during testing operations. Theswitch P when actuated also disables (at its contacts 5 and 6) the alarmcircuit previously traced through contacts 3 and 4 of relay LRI andcompletes an alarm circuit over contacts I and 2 of relay LR5, contactsI and 2 of relay V and over contacts 3 and 2 of switch P to ground.

Switch Q functions. to open the line L5 at its contacts 3 and 4 and tocomplete an alarm circuit to ground over its contacts 2 and I to contact5 of relay LRI,

Switch R is provided for the purpose of resetting the sub-stations bythe application of current over line LI after the sub-stations have gonedown (been de-energized) for any reason. Normally all the contacts areopen. When actuated to close its contacts, they perform the followingfunctions:

Contacts I and 2 of switch R complete a circuit from battery overcontacts I and 2 of switch G to the contact 2 of relay LRI to permitmagnet 55 of the annunciator to be energized in response to operation ofrelay LRI. Contacts 3 and 4 of switch R complete a shunt circuit throughcontacts 4 and 5 of switch G to short out the resistor and increase thecurrent delivered to line LI. Contacts 5 and 8 shunt out the relay T toprevent its operation in response to the excess current delivered to theline when resistor 80 is shunted out.

Switch G is provided for the purpose of creating an emergency setting tobe described in detail later. Th contacts I and 2 are normally closedbut when the switch is actuated, they open the circuit to the countingcontacts 2 and I of relay LRI to prevent operation of the countingmagnet 55. Contacts 3 and 4 are normally closed to permit shorting ofthe resistor 88 by actuation of the switch R previously described. Whenswitch G is actuated while switch R is also actuated, these contacts 3and 4 cut the resistor 80 back into the circuit to reduce the linecurrent to its normal value. Contacts 5 and B are normally open but whenthe switch is actuated they shunt the alarm contacts I and 2 of relay Vsince the latter relay is used as an alarm relay during emergency set-D.

Switch F is. provided for the purpose of resetting and countingsub-stations over line L5. The different contacts of this switch havethe following functions:

Normally open contacts I and 2 are provided to complete a circuit frombattery over the normally closed contacts 3 and 4 of switch E to thecounting contact 5 of relay LR5 to permit the latter to energize thecounting magnet 56. Normally closed contacts 3 and 4 are provided toshunt out the relay T and prevent its operation in response to theexcess current applied to line L5 during the counting operation.Normally open contacts 5 and 5 are for the purpose of applying batterythrough the contacts I and 2 of switch E, through the test jack 84,through the resistor 83 and through the relay LR5 and the contacts 3 and4 of switch Q to line L5. Normally closed contacts 6 and I are for thepurpose of disconnecting ground from the circuit last traced fromcontact '1 to line L5. Normally closed contacts 8 and 9 are for thepurpose of removing the shunt from resistor 83 during the countingoperation,

Switch E is for the purpose of setting up an emergency circuit over lineL5. Its contacts are normally closed. When the switch is actuated,contacts I and 2 are opened to remove the shunt from the resistor BI andreduce the current applied to line L5 to normal value. Contacts 3 and 4open the circuit from battery (over contacts I and 2 of switch F whenthe latter is operated) from the counting contact 5 of relay LR5 duringemergency setting.

Sub-station apparatus With one exception, which will be noted later, theapparatus at all of the sub-stations is identical. Referring to Fig, 2,each sub-station has a pair of line terminals 24 and 25, respectively,so arranged in the line circuit that when battery is applied to line LIat the central station, it flows into each sub-station at terminal 24.On the other hand, when battery is applied to line L5 at the centralstation, it flows into terminal 25 and out of terminal 24 at eachsub-station.

The essential elements at each sub-station may be broken down forconvenience into a unit A, a unit B, a lock switch N, a day loop DL anda night loop NL, and a ground loop GRL. The loops DL and NL may containvarious protective devices, such as door and window switches which areopened in response to abnormal conditions for which the system isintended to give an alarm. The day loop contains switches which aredesired for protection twenty-four hours of the day. The night loopcontains switches which are desired to protect only at times when thepremises are closed. Thus the night loop may contain door switches ondoors which are always closed when the premises are not occupied but maybe either opened or closed at other times. The ground may simply consistof a wire that is interlaced with the wires constituting the day andnight loops to make it more difficult for one to tamper with the day andnight loops without introducing ground thereon.

The lock switch N is used to cut the night loop into and out of thealarm circuit, and its operation will be described in detail later.

Each sub-station contains eight relays I, H, M, X, Y, Z, S and K,respectively. Relays I and H are shown in a separate unit A only forconvenience of description. These relays have the function of connectingthe sub-station circuit to the line terminals 24 and 25 in one or theother of three different ways, depending upon how current is enteringthe station. The three possible conditions of the apparatus shown inunit A are illustrated in Figs. 3, 4 and 5.

Fig. 3 shows the condition of unit A under normal line conditions whencurrent is entering the sub-station through terminal 24. It will beobserved that a circuit is completed from terminal 24 through a resistor32, through the relay H directly to a conductor 22; that a secondconductor 29 is connected to the conductor 22 within unit A through aresistor 38; and that terminal 25 is connected directly to a conductor2!. The particular circuit condition shown in Fig. 3 is created byvirtue of the fact that current is flowing through relay H and it ispulled, whereas relay I is short circuited by the closed contacts I and2 of relay H.

The circuit condition shown in Fig. 4 obtains when no current is flowinginto the sub-station through either terminal 24 or 25 because underthese conditions both the relays H and I are released. It will beobserved that conductor 29 is connected directly through relay I toterminal 25 and directly through relay H and resistor 32 to terminal 24,but the conductor 2! is isolated within the unit A. Conductor 22 isalways connected to the conductor 28 within the unit by the resistor 39.

Fig. 5 depicts the condition within unit A when current is entering thesub-station through terminal 25. Under this condition relay I is pulled,but relay H is short circuited. Terminal 25 is connected through relay Idirectly to conductor 22 and through resistor 31] to conductor 22, whileconductor 2| is connected through resistor 32 to terminal 24. It will beobserved that regardless of the condition of relays I and H, a pair ofconductors 26 and 2'! are always connected to opposite ends of theresistor 32.

Unit B contains relays M, X, Y, Z, S and K.

Relay M is a slow release relay that is normally down, but is pulled andreleased during a reset- 6 ting operation to produce a currentinterruption that actuates the annunciator 54 at the central station.

Relay X is a slow to operate relay and cooperates with relay M to insurethat the latter will be fully saturated before it releases.

Relays Y and Z are slow-release relays and are brought into operationonly under certain conditions to be described later. Their function isto introduce a time lag between the resetting of successivesub-stations.

Relay S is a slow release relay that is normally operated but falls downin response to interruption of its operating current for a predeterminedinterval of time. It cooperates with relay M to produce a countingimpulse in the line when the station is reset.

Relay K is a fast action relay which is normally pulled, but falls downin response to any current interruption on the line, to complete a pathto ground through resistor 3|, and to out the resistor 32 into the linecircuit.

Resistor 30 is provided for the purpose of holding relay H or relay Iover a circuit including c0nductor 26 and back contacts of relays S andM to ground when the loop is opened.

Resistor Si is provided to permit relay K to pull if a path for currentis provided to the next station over conductor 2!. If the resistor 3|were omitted and contact 4 of relay K were connected directly to ground,no potential would be applied to the winding of relay K, and it wouldnot pull even though there were a path through the relay to ground atthe next station.

Resistor 32 is provided in series with the line terminal 24 and is cutinto the circuit whenever relay K is down to provide a safety factoragainst relay M pulling except when the line current is increased byactuating switch R at the central station.

The shunt 33 which is provided at odd numbered stations only is for thepurpose of disabling the relays Y and Z only at the odd stations whentesting over line L5 from the central station to thereby distinguishbetween odd and even numbered stations. The operations involving theshunts 33 will be fully described hereinafter.

Operation in response to temporary trouble at sub-station ST#3 As hasbeen previously indicated, current normally flows from battery at thecentral station out over line Ll. through all the sub-stations and backover line L5 into the central station. The circuit at the centralstation is indicated in heavy lines.

The normal circuit at a sub-station when the latter is adjusted fornight operation is also illustrated in heavy lines in Fig. 2. It will beobserved that unit A is in the condition shown in Fig. 5 so that theline current flowing in through terminal 24 is shunted around theresistor 32, over conductors 26 and 2'! through the contacts I and 2 ofrelay K, through relay H, through contacts 1 and 8 of relay I, throughcontacts 3 and 5 of relay H, through conductor 22, through contacts Sand5 and contacts 2 and I of the lock switch N, through the night loop NLand through the day loop DL and over a conductor 23 into the unit B;thence through contacts I and 2 of relay Y, over contacts 6 and 4 ofrelay over contacts 8 and l of relay M, through relay S, through relayK, through the contacts I and 2 of relay Z to conductor 2!, and thence 7through unit A to terminal 25. Hence, relays H. S and K are pulled atall of the sub-stations.

Now assume that a temporary open occurs in one of the loops DL or NL atthe sub-station ST#3.

At the central station this interrupts the line current, causin relaysLRI and LR to drop, opening the alarm circuit to relay C and causing thelatter to release and ring the bell 51 and light the lamp Lrd.

At sub-station ST#1 relay K drops due to the interruption of current,but after dropping, relay K completes a path to ground through relay Sover contacts 3 and 4 of relay K and through resistor 3|. This providesa path to ground for relay H. Current is also reapplied through relay Sso that it holds. The path is, therefore, still completed through relayK and out through terminal 25 to the next sub-station SK#2. As will bedescribed next, the same operation takes place at sub-station ST#2 sothat current is restored through relay K, causing it to pull. Hence, allthat happens at sub-station ST#1 is a momentary release and re-pullingof relay K.

At sub-station ST#2, relay K dropped simultaneously with relay K atsub-station ST#1, but when relay K at sub-station ST#2 fell, it provideda path to ground for the re-energization of relay K at sub-station ST#1and when the latter relay pulled, it took the ground on the line atsub-station ST#1 and applied full current to sub-station ST#2. Relay Sheld. This left sub-station ST#2 with relays H and S pulled, but withrelay K down, because the loop was still open at sub-station ST#3 andthere was no path for current to flow to ground at sub-station ST#3.

At sub-station ST#4 all current was cut off b the Opening of the loop atsub-station ST#3 so that relays H and K release at that station.

Because of their slow release characteristics, none of the relays S dropuntil after the foregoing operations have been completed. However, afteran interval, relays S at sub-stations ST#3 and ST#4 do drop.

At sub-station ST#3 the release of relay S completes a direct path toground from conductor 20 over contacts 2 and I of relay S and contacts 9and ID of relay M, contacts 1 and 8 of relay S, and ground loop GRL. Atthis time, unit A is in the condition shown in Fig. 4, so that there isa path to ground from relay H over conductor 20.

This leaves sub-stations ST#1 and ST#2 in normal condition completingthe circuit to ground at sub-station ST#3, and with all the relays downat sub-station ST#4.

Let it be assumed that the temporary opening in the loop at sub-stationST#3 was caused by a burglar opening a door but that the door was closedagain immediately after the foregoing operations have occurred,

The reclosing of the loop circuit at sub-station S'I'#3 completes acircuit from conductor 22 through the loop circuit to conductor 23 andthrough the contacts I and 2 of relay Y, contacts 6 and 5 of relay S,through contacts 1 and 6 of the lock switch N and contacts 9 and ID ofrelay I, through relay M, contacts 5 and 4 of relay M, and contacts Iand 8 of relay S to ground, but the normal line current is insufficientto pull relay M,

Therefore, the restoration of the loop circuit does not change thepositions of any of the relays in the system.

It will be recalled that immediately upon the initial opening of theloop at sub-station ST#3, the line relays LRI and LE5 at the centralstation released to give an alarm signal. Let it be assumed that afterthe loop has been restored as described, the operator at the centralstation responds to the alarm and tests to determine where the troublecondition was. To do this he performs the following operations:

First, the operator at the central station actuates the switch R, whichshunts out the resistor 89 and increases the current in the line. Thisincreased current flows through sub-stations ST#1 and ST#2 (which hadalready automatically restored to normal condition), and through'relay Mat sub-station ST#3 to ground, pulling relay M. The pulling of relay Mcuts the slow to operate relay X into the circuit. Thus, the currentafter leaving relay M flows over contacts 5 and 3 of that relay, throughrelay X and contacts I and, 2 thereof. After a delay, relay X pulls, andthis completes a circuit from contact I of relay X to contact 3 thereofand thence over contacts 5 and I of relay M, through relay S and overcontacts I and 2 of relay M to ground. Relay S thereupon pulls andshunts relays X and M out by completing a circuit over contacts 6 and 4of relay S through contacts 6 and I of relay M and through relay S toground over contacts I and 2 of relay M. After an interval of time,relay M releases, and in releasing, it momentarily opens the circuitwhile the movable contact 1 is swinging from contact 6 to contact 8.This interrupts the main line circuit through line relay LRI, to actuatethe indicator thereat in a manner to be described. When relay M hasfully released and its contact 1 is closed on contact 8, the circuit isrestored through relay S and through relay K to conductor 2| and thenceto sub-station ST#4.

At this time unit A at sub-station ST#4 is in the condition shown inFig. 4, in which there is a path to ground from terminal 24 throughrelay H over line .20 and the back contacts of relays S and M to groundso that relay H operates, restoring the condition of unit A to normal,as shown in Fig. 3. Thereupon the apparatus at sub-station ST#4 operatesexactly the same as last described in connection with sub-station ST#3to first pull relay M, then pull relay X, then pull relay S and releaserelay M to again momentarily interrupt the line current over line LI andleave the relays at the station restored to normal condition.

As has been previously described, up to the time when the operator atthe central station actuated the switch R, normal current was flowingfrom the battery 5| through the resistors 82 and 88 and the relays LRI,T and V out over line Ll to ground through relay M at sub-station ST#3,but the normal line current was insufficient to operate relay M.

When the operator actuated the switch R, it shunted out the resistor andthe relay T, increasing the line current to a value sufiicient to pullrelay M at sub-station ST#3. At the same time switch R applied batteryto the counting contact 2 of the relay LR] and over contact I of therelay to the counting magnet 55 of the annunciator 54 which pulled thelatter to step the hand 12 counter-clockwise one space (leaving the handstill one space ahead of the numeral 1 on the annunciator).

When the relay M at sub-station ST#3 pulled, it did not interrupt theline current because at that time relay S was not pulled and the contactI of relay M was not in the line circuit. However, after relay S pulledand released relay M, the contact I of relay M was in the path from theline to ground so that while the contact 1 was moving from contact 6 tocontact 8, the line current was momentarily interrupted long enough tolet relay LRI at the centnal station fall back momentarily, therebystepping the hand 12 another space leaving it in front of the numeral 1.

As has already been described, the release of relay M at sub-stationST#3 took the ground off the line at sub-station ST#3 and applied theline current over the line 4 to sub-station ST#4 where it operated therelays in the sequence previously described in connection withsubstation ST#3 to first pull relay M, then pull relay S and thenrelease relay M to again momentarily interrupt the line current, takethe ground off of station ST#4 and complete the circuit through line L5back into the central station. The interruption of the line current byrelay M at substation ST#4 again actuated the counting magnet 55 to stepthe hand 12 another space into position midway between the numerals 1and 2. This indicates to the operator that two stations have beencounted and he knows that they represent the number of stations beyondthe point where the temporary open occurred. In other words, he know-sthat he has counted the number of stations between the point where theopen occurred and line L5. Hence, he knows that the temporary open Wason the loop at station ST#3.

It will be noted that if the loop at sub-station ST#3 had beenpermanently opened instead of temporarily opened, then the circuit wouldnot have been completed through relay M at substation ST#3, and therewould have been no current interruption following the closure of switchR at the central station. Hence, the hand 12 would have moved up onlyone space and stopped. This would have apprised the operator that atrouble condition still existed on the circuit and he would proceed tomake a routine test to locate the trouble as follows:

First, he restores switch R. and then actuates switch P. This groundsthe heavy line circuit at the central station between relays LRI and T,to hold relay LR! and provide a path to ground from line LI whiletesting over line L5. It also disables the subsidiary alarm circuit overcontaots 3 and 4 of relay LR5 and completes an auxiliary alarm circuitover contacts I and 2 of relay LE5 and the contacts of relay V. Ofcourse, the grounding of the line between relays LR! and V interruptsthe flow of current out over line Ll.

The operator then again actuates switch R, again applying battery to thecounting contact 2 of relay LRI and stepping the hand 12 another space,leaving it standing to the right of the numeral 1.

The operator then restores switch P, which puts current out on line LIthrough relay V again and causes the sub-stations to successivelyinterrupt the line current and complete the circuit on to the nextstation up to the point where the loop is open. All of the stations upto the open are counted at this time because all the relays at thestations were previously released by actuation of switch P. In thepresent instance, it has been assumed that the loop is open atsub-station ST#3, so only sub-stations ST#1 and ST#2 will interrupt theline current, thereby causing the hand 12 to stop in position midwaybetween the numerals 2 and 3.

The operator next restores switch R and again operates switch P.

The operator then actuates the switch F. This applies battery over'contacts I and 2 of switch E and contacts 5 and 6 of switch F, throughthe resistor 83 and through the line relay LR5 to line L5. It alsoapplies battery over contacts I and 2 of switch F and contacts 3 and 4of switch E to the counting magnet 5 of relay LE5, so that when thelatter relay pulls, the counting magnet 53 is energized to step the lefthand 62 one space into position just to the left of the numeral 4.Thereafter, the sub-stations are successively reset over line L5 up tothe point where the open occurred, each station as it resets producing amomentary interruption that drops the line relay LR5 and actuates themagnet 55 to step the hand 62 another space. Since, in the presentinstance, the open is at sub-station ST#3, the hand 62 steps only onespace and is left midway between the numerals 4 land 3. Therefore, thenumeral 3 is boxed by the hands 12 and 62, which tells the operator thatthe trouble condition is at substation ST#3.

It may be noted at this point that if the trouble, instead of being insub-station ST#3, were in the line between two stations, say betweensubstations ST#2 and ST#3, both of the hands 82 and 12 would havestepped into the same position which, under the conditions described,would be midway between the numerals 2 and 3, because the hand 52 wouldhave been moved twice in response to the interruptions produced bysubstations ST#4 and ST#3, respectively, and the hand 12 would likewisehave been moved two spaces by the two interruptions produced bysubstations ST#1 and ST#2, respectively. The system, therefore,distinguishes between a trouble condition within a station and a troublecondition on the line between stations.

Emergency setting It is possible with the present system after a troublecondition has developed at one substation to place the system in anemergency setting and cause it to respond to a new trouble conditionthat may develop at one of the other stations.

At the end of the last operation described, current was feeding intoline L5. Then the operator actuates switch R. and restores switch P,after which he switches G and E. This takes battery 01f the countingcontact 2 of relay LRI and the counting contact 5 of relay LE5,de-energizing the counting magnets 55 and 56. The actuation of switchesG and E also cuts in the resistors and BI, thereby reducing the linecurrent going into both lines LI and L5 to normal value. The oper atorthen manually restores the hands 62 and 12 of the annunciator 54 totheir normal positions and restores the relay C by pressing the pushbutton U. The system is now in emergency condition and is capable ofresponding to an alarm condition at any one of the sub-stations ST#1,ST#2 or ST#4, despite the fact that an alarm condition is alreadyeXisting at sub-station ST#3.

If a second open occurs on line Ll, it will release the line relay LR!and release the trouble relay C. Likewise, new open condition on line L5releases the line relay LRB and releases the trouble relay C.

To locate the new trouble condition the operator restores switches R, G,F and E to their normal positions, thereby causing line relay LE5 todrop, but the line relay LRl holds. The operator then actuates switch Pwhich holds the relay 11 R. b dr s the relairY an the re ays at thesub-statiorisd'n line'Ll. The operator then actuates switch 3. which, aspreviously described, mo h hand one s ace i The ne o he restores theswitch? which causes" the system to] count. the stations in line Ll upto the point of the'new trouble condi on if it is in line Ll. If the newtrouble condition is not in line Ll, the"hand 112' is again stepped upinto position midway between the numerals 2 and 3 on the annunciator 5Q,advising the operator that the second alarm condition was not created atsubstation ST#1 or; The operator then actuates switch 'Rcaus hg thesystem to count the stations on line' L5 up to the second alarmcondition thereon. After the location of the second alarm has beendetermined, the operator again} actuates switches G and El and manuallyrestores. the annunci'ator hands 62 and 12 and presses the push buttonUte reset the trouble relay C, thereby. again restoring the system toemergency settinglin which it will respond to a third: trouble conditionthat may occur on the portions of the lines LI and L5 that are stillintact. ltql ttt'ne supewisz'nn ofsystem The p at r at h Qfl lilf l i @3m a routine checlganddefinitely determine whether or not all 'of'th"sub- 'stations are operative and all of the line sections are intact,including the line sections Ll" n'd Llifwhich are adjacent the centralstation. This routine check is performed asfollowsz The operator firstactuates the switch P to place current on the line between the relaysLRI and v: to hold'ife'lay whi e cutting n the current to 'thesubstations (dropping all relays atthesub-stationsl'and'dropping relays Vand LR5. The operatonrie'xt "actuatesswitch R to shunt out the relay' Tandapply battery to the counting contact 2, of. relay LRI, which causesthe hand 12 to step one space. This operation also shunts the resistor-80 to increase the line ur ent The operator than, restores switch P.to. reconnect theline'relayLRl, to the lineLl and apply the heavy orsuper normal current to the line. aswa ne that an, of the sub-stationsare'intact and; that thelines Ll, L2, L3. and L4. are intact, thesub-stations reset in, sequence, moving the hand I? into positioniiustto the right of or head; of, the numeral 4 on the annunciator, thereby.accounting for. all stations. However, this doesnpt establish. that1ine,L5 isintact from substatiphfi'fik into the central station. Theoperator then restores switch R. to normal posi- 'tion to out in theresistor, take the shunt ofi relay T and; lie-energize the magnet 55,afterv which he presses the push button U. If the line L5 fromsubstation S'IT#4; is intact, relay LE5 will be pulled and the troublerelay, C will pull over the contacts 3 and 4 of relay LR5 and thecontacts {and 4-01, relay LRL Having pulled, the trouble relayc willholdover, its contacts I: and 2, thereby indicating that the entiresystem is in norma c nd ion.

'lhe ore o n test will detect. any abnormal on iti n n th line.

Supervising switch-over from day to nightf whichtheloc lgv switch N, at.each. sub-station was- 'ihl t 3% ac oss a ofa relay Y. TAt'tlieevenInumbered stations, the

shunt 31 m abut' tsff wise -P ?P. m.$d by a pair of contacts {land illon the relay I, which contacts are closedwhen relay I is de-energized.Relay I is always tie-energized except when the sub-stationsareenergized by current transmitted over line' L5 from the centralstation. During normal operation current flows out from the centralstation over line Ll to the substations and hence normally thecondutcors 28 and 29 are connected directly to the contacts fi andl ofthe lock switch at'all stations, either by the contacts 9 and [ll ofrelay I or bythe shunt 33.

Whenever the conductors 28 and 29 are shorted, the. relay Y is disabledso that this relay and relay Z remain inactive and play no part in theoperation of the circuit.

However, it will be observed that whenever conductors Z8 and 29 areopened exterior of the unit B, the relayY is connected in series withthe relay M and the loop circuit. Thus the cir-. cuit can be traced fromth loop through QQll-w ductor 23-, through the contacts l and-2 of relayY, through the contacts 6 and 5 of relay S, thence through relay Y torelay M. When relay Y pulls, it opens itscontacts I and 2, therebycutting rela Z into the circuit ahead of relay Y. When relay Z pulls, itopens, the contacts I and 2 which are interposed in the conductor 2|leading to the next sub-station. Hence, the circuit cannot be completedto the, next substation (following the energization of relay S and theconsequent release of relay M to, give the counting interruption) untilrelays Y .and Z are released. The circuit over which relays Y and Z areener-. gized is openedat contacts 5 and fi of relay S when the latteroperates, but both Y and Z are slow release relayssothat an appreciableinterval of time is introduced between the pulling. ofrelays and therelease of relay Z to complet the circuit ontothe neXtsub-station.following the resetting of the instant sub-station.

Ifhe overall effectof the. relaysY and-Z, and the contacts. 5, and 1. ofthe lock. switch N, is that during a routine supervisory test from thecentral. station oven lineLLl thehand. 12 of the annunciator 54, movesin rapid steps from a position to the right of the numeral 1 intoposition, to the right of numeral 4,i-f. thelookswitchesN at all of thesub-stations are in night position. On the other hand, if: all of thelock switches N arein day position, the handf'll at the central stationwill pause a readily perceptible in.-. terval (which may be intheneighborhood of two seconds) between each stepping operation. On theother hand, if some of the sub-stations are in i i and thsr-s lbfit tinsare in petit on h operator a h entral station is apprised bytheresultant slow or fast operation of thehand J? at dii ferentportionsof; its..travel just whichstationshave been switchedl t- P 3 19; e dawhih- Sta ion h v not been switched.

khe p w dutaa a tat oa switching from a t g t os t on ma e. a -followszhe operator; at the sub station, inserts a key in the c 5 t e oq benemthe positiomshown in Fig. 6 during day. operation) and;turnsthe,lockclockwise. The lock is always free to rotate clockwise a distancesufficient to cause contacts I and to ride onto the low portions of camsN4 and N3, but further movement may be limited by engagement of a magnetactuated pawl N6 with a shoulder N59 on the cam N8. The initial movementtransfers contact 3 from contact IE to contact 5, opens contacts i and 2and closes contacts 6 and E. This connects the conductor 22 overcontacts 3 and 5 and through the magnet N to the night loop and if theloop is intact, the magnet N28 is energized to release the dog N6 fromthe shoulder Nii! on cam N9 and permit the operator to rotate the lockthrough 180 and remove his key. The final rotation of the cam N4 againcloses contacts l and 2 to shunt out the magnet N20.

The operation described is usually performed before the operator leavesthe premises. Let it be assumed that to leave the premises he has toopen a door that is protected by the night loop so that in leaving thepremises he sends in an alarm. The operator at the central station thenmakes his routine test over line Li as previously described. Let it beassumed that the alarm was produced by the operator at substation STt Zleaving the premises so that sub-station ST#2 is in the night position,whereas stations ST#1, ST#3 and ST#4 are still in the day position. Theoperator at the central station will be apprised of this fact by theaction of the annunciator hand 72. Thus this hand, after stepping intoposition ahead of the numeral 1 in response to the interruption ofcurrent produced by relay M at sub-station STitl, will pause beforestepping across the numeral 1 because the relays Y and Z 1 atsub-station S'Iail will introduce an additional time delay before thecircuit is completed from sub-station ST#l to sub-station ST#2. Thistells the operator at the central station that substation ST#1 is stillin the day position. However, after stepping across the numeral 1 inresponse to the current interruption produced by relay M at sub-stationST#2, the hand 12 will step rapidly across the numeral 2, therebytelling the operator at the central station that sub-station ST#2 is inthe night position.

Following the operation at sub-station ST#3, there is a pause before thehand 72 steps across the numeral 3 indicating that sub-station ST#3 isstill in day position. Since the hand moved into position between thenumerals 3 and 4 in response to the interruption produced by theresetting of station STit l, it will remain in that position. However,the operator is apprised as to whether or not sub-station ST#4 is in dayor night position by the time required for relay LE5 in the centralstation to pull following the movement of the hand I2 into positionbetween the numerals 3 and 4. He obtains an indication of the time whenrelay LE5 pulls by holding the push button U down so that the lamp Lrdgoes out in response to the pulling of relay LE5.

As each sub-station is switched from day to night position, the circuitwill be interrupted as described and the operator at the central stationwill perform his routine test so that he can keep a record of the timeat which each sub-station was switched into night position.

To switch the sub-stations from night position into day position, it issimply necessary for the operator at the sub-station to insert his keyin the lock N5 and rotate it counter-clockwise 180 back into theposition shown in Fig. 6. The lock dog N6 does not function during thisoperation because the night loop is being cut out of 14 the circuit andthere is no occasion for testing to see that the loop is intact.

Location of sub-station completely removed from circuit The provision ofthe shunts 33 at alternate stations (the odd numbered stations in thisinstance) enables the operator at the central station to determine thelocation of a sub-station that might be completely removed from theline, as by shunting. Thus let it be assumed that the present inventionis incorporated in a burglar alarm system and that a clever burglar,prior to burglarizing the premises at sub-station ST#3, placed a shuntbetween lines L3 and L5 and cut sub-station ST#3 completely out of thecircuit.

A routine test made over line L! would apprise the operator at thecentral station that one of the sub-stations had been cut out of theline because impulses to actuate the hand 72 of the annunciator would bereceived from only the three remaining stations. However, this routinetest would not inform the operator which station had been removed fromthe circuit. The operator can determine the location of the missingstation by making his routine test over line L5 in the manner previouslydescribed.

Thus, whereas when testing over line Ll the relays H at the sub-stationsare energized, the relays I remain de-energized and therefore thecontacts 9 and lo on the relays I remain closed and the relays Y areshunted out at all stations. On the other hand, when the test is made byapplying current to line L5, the relays I are energized instead of therelays H, and the energization of the relays I at the even numberedsubstations opens the shunt around the relays Y at those stations,permitting them to operate and introduce a time delay.

Hence, when testing over line L5, sub-station STit, after delivering itsimpulse to actuate the hand 62 into position to the right of the numeral4, does not complete the circuit rapidly to line L4 because relay Iopened the shunt and out in relay Y, which, in turn, out in relay Z,which opened the contacts I and 2. This held the circuit at station ST#4for a predetermined interval.

The operator at the central station, therefore, gets a normal movementof the hand 52 in response to the impulse from sub-station ST#4.However, since sub-station ST#3 is cut out of the circuit, the resettingof station ST#4= completes the circuit onto sub-station ST#2, and thetransmission of the impulse from sub-station ST#2 is delayed by virtueof the fact that the open contacts 9 and H] of relay I at sub-stationST#4 caused the operation of the relays Y and Z at that station.Following the transmission of the impulse from sub-station ST#2, theconnection to sub-station ST#1 is also delayed because there is no shunt33 at station ST#2. Hence, the operator gets a delayed movement of thehand 52 in response to the current interruption at substation ST#1.

If sub-station ST#3 had not been cut out of the circuit, the operator atthe central station would have obtained a normal movement of the hand 52in response to the current interruption from sub-station ST#4; a delayedmovement of the hand from the current interruption at substation ST#3; anormal movement of the hand from the interruption at sub-station ST#2;and a delayed movement of the hand from the interruption at sub-stationST#1. The fact that both the second and third movements of the hand weredelayed, tells him that it is sub-station ST#3 that has been removedfrom the circuit.

As another example, let it be assumed that station ST#2 is cut out ofthe circuit. The operator at the central station when testing over lineL will then get a'normalmovement of hand 62 from station ST#4; he willget a delayed movement of the hand from station ST#3; and he will get anormal movement of the hand from station ST#1. Thisoperation issufiicient to apprise him of the fact that station S'I-#2 is the onethat has been removed from the circuit.

As a further example, let it be assumed that station ST#1 is removedfrom the circuit. In response to a test over line L5 the operator at thecentral station will obtain: normal movement of the hand in response tothe current interruption from station ST#4; a delayed movement of thehand in response to the interruption from station ST#3; and a normalmovement of the hand in response to the interruption from station ST#2.It will be observed that this indication is the same as that that wasobtained when station ST#2 was the one that was removed from thecircuit. To distinguish between the two situations, the operatorobserves the further action of the system after the last station stillin the circuit has been reset. Thus following the resetting of the laststation, the current enters the central station on line LI and flowsthrough relay V to ground at contact I on switch P. Relay V thereuponpulls, closing a circuit to ground from the switch P over the contacts Iand 2 of relay LR2 and contacts I and 2 of relay T through relay C andpush button U (which the operator is holding closed) to battery, therebypulling relay C to extinguish the red light Lrd.

If station ST#2 was the one that was removed from the circuit, the redlight is extinguished quickly followin the last movement of the hand 62.On the other hand, if station ST#1 was the one that was removed from thecircuit, a time delay occurs before the red light Lrd is extinguished.

Miscellaneous details It will be observed that contacts 2 and 3 of relayS at eachsub-station short circuit the resistor 30 when relay S ispulled. The purpose of this is to stabilize the line current during theinterval that the sub-stations are impulsing.

Various values of potential and resistances may be employed in thesystem, depending upon various' factors, including the number ofsub-stations to be actuated. However, in a typical system employing foursub-stations, elements having the following values may be employed,where the potential of source 5| is 60 volts and the nominal normal linecurrent is 15 milliamperes.

As has been previously indicated, the resistors 32 at the sub-stationsare cut in only when the relays K are down and are to keep the currentfairly constant during the resetting operation only. These resistors 32preferably have difierent values at different stations. Thus, at stationS'I-#l, resistor 32 may have a value of 800 ohms; at station ST#2 it mayhave a value of 400 ohms; at station S'I#3 it may have a value of 200ohms; and at station ST#4 it may be entirely omitted or have a value ofzero ohms.

Various departures may be made from the exact construction shown anddescribed without departing from the invention which is to be limitedonly to the extent set forth in the appended claims.

I claim:

1. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit, anda common current path between all said stations, in which said centralstation includes means for selectively supplying either a normal currentor a super-normal current to one end of said line, and counting meansfor counting interruptions in current flow to said line, and in which atleast one of said sub-stations includes: a normally closed protectiveloop; first means responsive to flow of current through said loop intosaid line circuit for maintaining said sub-station in a normal conditionin which said loop is connected in series in said line, and responsiveto interruption of current through said loop for connecting the loopbetween said one end of the line and said common path; and second meansresponsive to prolonged interruption of current from said loop followedby flow of super-normal current from said loop for momentarilyinterrupting current flow from the central station to that substationand then restoring said sub-station to normal condition.

2. A system as described in claim 1 in which said second means comprisesfirst and second slow release relays, said first relay being in serieswith said loop and normally energized over its own holding contacts andwhen de-energized connecting said second relay between said loop andsaid common path, said second relay being responsive only tosuper-normal current and when energized connecting said first relaybetween said loop and said common path to energize said first relay andthereby de-energize said second relay, and contact means on said secondrelay formomentarily interrupting current flow into said substationduring release of said second relay.

3. A system as described in claim 1 in which said second means comprisesfirst and second slow release relays and a third slow-to-operate relay;said first relay being normally in series with said loop andenergizedover its own holding contacts and when de-energized connecting saidsecond relay between said loop and said common path; said second relaybeing responsive only to super-normal current and when energized con- 4.A system as described in claim 1 including adjustable resistor means atsaid central station in series with said current supply means and saidone end of said line.

5. A system as described in claim 1 in which at least one of saidsub-stations includes a resistance element in the circuit between saidone end of said line and said second means, and the said first meansincludes means for shunting said resistance element only while said onesub-station is maintained in said normal condition.

6. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit, anda common current path between all said stations, in which said centralstation includes means for selectively supplying either a normal currentor a super-normal current to one end of said line, and counting meansfor counting interruptions in current flow to said line, and in which atleast one of said sub-stations includes: relay means responsive tocurrent flow from the substation into the line for normally maintainingthe sub-station connected in series in the line, said relay means beingresponsive to current interruption to establish connection to saidcommon path at that sub-station, and including means responsive only tofiow of said super-normal current through that sub-station to saidcommon path for momentarily interrupting said super-normal flow andrestoring that sub-station to normal condition.

'7. A signaling system comprising a central station, a line circuithaving two ends entering said central station, a plurality ofsub-stations connected in series in said line circuit and a commoncurrent path between all said stations in which said sub-stations eachinclude: switching means operable in response to current flow throughthat sub-station from either adjacent line section to said common pathfor momentarily interrupting said current flow and switching saidcurrent from said common path into the other adjacent line section; saidcentral station including a source of current having one terminalconnected to said common path, first and second line relays, and aresistor, switching means for selectively either connecting said firstline relay between the other terminal of said source and one end of saidline and connecting the second line relay between said one terminal ofsaid source and the other end of said line, or connecting said secondline relay and said resistor in series between said other terminal ofsaid source and said other end of said line.

8. A signaling system comprising a central stasection to said commonpath for momentarily interrupting said current flow and switching saidcurrent from said common path into the other adjacent line section, atleast one of said substations including means for introducin a timedelay between current interruptions produced by a pair of successivesub-stations.

9. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit and acommon current path between all said stations, in which said centralstation includes means for applying potential between said common pathand one end of said line, and means for counting interruptions incurrent fiow to said line, and in Which said sub-stations each include:switching means operable in response to current flow through saidsub-station from one adjacent line section to said common path formomentarily interrupting said current flow and switching said currentfrom said common path into the other adjacent line section, at least oneof said sub-stations including means for introducing a time delaybetween the momentary interruption of current flow and the switching ofsaid current from said common path into the other adjacent line section.

10. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit and acommon current path between all said stations, in which said centralstation includes means for applying potential between said common pathand one end of said line, and means for counting interruptions incurrent flow to said line, and in which said sub-stations each include:switching means operable in response to current flow through saidsub-station from one adjacent line section to said common path formomentarily interrupting said current flow and switching said currentfrom said common path into the other adjacent line section, at least oneof said sub-stations including slow action relay means having contactsin the circuit to the said other adjacent line section and actuatedunder control of said switching means for delaying application ofcurrent to said other adjacent line section following said momentaryinterruption.

11. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit, anda common current path between all said stations, in which said centralstation includes means for applying potential between said commoncurrent path and one end of said line, and means for countinginterruptions in current flow to said line, and in which saidsub-stations each include switching means operable in response tocurrent flow through said sub-station from on adjacent line section tosaid common path for momentarily interrupting said current flow andswitching said current from said common path into the other adjacentline section; at least one of said sub-stations also including a pair ofnormally closed protective loops and loop switching means operable intotwo positions for selectively either connecting one loop only orconnecting both loops in series with said one adjacent line section,said one sub-station also including means for introducing a time delaybetween the interruption produced at that sub-station and theinterruption produced at a next adjacent sub-station, and

means for rendering said time delay means operative in one position ofsaid loop switching means and inoperative in the other position thereof.

12. A signaling system comprising a central station, a line circuit, aplurality of sub-stations connected in series in said line circuit, anda common current path between all said stations, in which said centralstation includes means for applying potentia1 between said common pathand one end of said line, and means for counting interruptions incurrent flow to said line, and in which said sub-stations each include:switching means operable in response to current flow through thatsub-station from one adjacent line section to said common path formomentarily interrupting said current flow and switching said currentfrom said common path into the other adjacent line section, one set ofalternate substations each including means for introducing a time delayadjacent the momentary interruption produced at that sub-station.

13. A signaling system comprising a central station, a line circuithaving two ends entering said central station, a plurality ofsub-stations connected in series in said line circuit, and a commoncurrent path between all said stations, in which said central stationincludes means for selectively applying potential between said commonpath and ither end of said line, and means for counting interruptions incurrent flow to said line; and in which said sub-stations each includeswitching means operable in response to current flow through thatsub-station from either adjacent line section to said common path formomentarily interrupting said current flow and switching said currentfrom said common path into the other adjacent line section; at least oneof said sub-stations including means for introducing a time delaybetween successive current interruptions; and time delay control mean atsaid one sub-station selectively responsive to the entry of current fromopposite ends of said line, whereby said time delay means functions inresponse to current from one end of said line but not in response tocurrent from the other end of the line.

14. A signaling system comprising a central station, a line circuithaving two ends entering said central station, a plurality ofsub-stations connected in series in said line circuit and a commoncurrent path between all said stations, in which said central stationincludes means for selectively applying potential between said commonpath and either end of said line, and means for counting interruptionsin current flow to said line; said sub-stations each including switchingmeans operable in response to current flow through that sub-station fromeither adjacent line section to said common path for momentarilyinterrupting said current flow and switching said current from saidcommon path into the other adjacent line section; at least one of saidsub-stations including a pair of normally closed protective loops andloop switching means operabl into two positions for selectively eitherconnecting one loop only or connecting both loops in series with anadjacent line section, said one substation also including means forintroducing a time delay between the interruption produced at thatsub-station and the switching of said current from said common path intothe other adjacent line section; and means for rendering said time delaymeans operative in response to positioning of said loop switching meansin one only of said two positions and entry of line current into 20 thatsub-station from one only of the two adjacent line sections.

15. A system as described in claim 12 including means at said centralstation for indicating current flow from the other end of said line intosaid central station.

16. A signaling system comprising a central station, a line circuithaving two ends entering said central station, a plurality ofsub-stations connected in series in said line circuit, and a com moncurrent path between all said stations, in which said central stationincludes means for selectively applying potential between said commonpath and either end of said line, and means for counting interruptionsin current flow t said line; and in which said sub-stations each includeswitching means operable in response to current flow through thatsub-station from either adjacen-t line section to said common path formomentarily interrupting said current flow and switchin said currentfrom said common path into the other adjacent line section; means forintroducing a time delay between successive current interruptions; andtime delay control means at one set of alternate sub-stations forselective rendering said time delay means inoperative in response toentry of current from one end of said line and operative in response toentry of current from the other end of said line.

17. A signaling system comprising a central station, a line circuithaving two ends entering said central station, a plurality ofsub-stations connected in series in said line circuit, and a commoncurrent path between all said stations, in which said central stationincludes means for selectively applying potential between said commonpath and either end of said line, and means for counting interruptionsin current flow to said line; and in which said sub-stations eachinclude switching means operable in response to current flow throughthat sub-station from either adjacent line section to said common pathfor m0- mentarily interrupting said current fiow and switching saidcurrent from said common path into the other adjacent line section;means for introducing a time delay between successive currentinterruptions; time delay control means at one set of alternatesub-stations for selectively rendering the time delay means at thosesub-stations either operative or inoperative independently of the end ofthe line from which current enters those sub-stations; and time delaycontrol means at the other set of alternate sub-stations for selectivelrendering the time delay means at those sub-stations either operative orinoperative in response to current entering from one end of said line,and rendering the time delay means inoperative in response to currententering from the other end of the line.

FELIX F. DENZLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 967,633 Goldstein Aug, 16, 19102,220,371 Hopkins Nov. 5, 1940 2,234,940 Hopkins Mar, 11, 1941 2,157,864Phinney 1- May 9, 1939

